US President George Bush assures Israeli Prime Minister Ehud Olmert that the United States stands with Israel after the "barbaric and vicious attack" on a school in west Jerusalem.

US President George W Bush has assured Israeli Prime Minister Ehud Olmert that the United States stands with Israel after the "barbaric and vicious attack" on a school in west Jerusalem.

"I have just spoken with Prime Minister Olmert to extend my deepest condolences to the victims, their families, and to the people of Israel. I told him the United States stands firmly with Israel in the face of this terrible attack," Bush said in a written statement released by the White House.

At least eight people were killed on Thursday night when a Palestinian gunman opened fire inside a Jewish religious school in Jerusalem in an attack threatening peace efforts amid escalating violence.

"I condemn in the strongest possible terms the terrorist attack in Jerusalem that targeted innocent students at the Mercaz Harav Yeshiva. This barbaric and vicious attack on innocent civilians deserves the condemnation of every nation," said Bush.

The Jerusalem attack came after more than a week of flaring Israeli-Palestinian violence in and around the Hamas-run Gaza Strip, where more than 130 Palestinians have been killed in eight days.

In Beirut, Hezbollah's television announced that the authors of the Jerusalem attack were members of a previously unknown group called "Phalange of Free Men of Galilee -- Groups of the Martyr Imad Mughnieh and Martyrs of Gaza."

The claim was made in a tag line running across the bottom of the screen, and no further details were immediately given. Hezbollah official Nawaf Moussaoui, reached by AFP, said he had no comment on the attack.